<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>jquery--入门</title>

    <script src="js/jquery-3.4.1.min.js"></script>
    <script>
        $(function () {
            $("button").click(function () {
                alert("jquery 第一个入门案例")
            });
        });
    </script>
</head>

<body>
    <button>按钮</button>
</body>

</html>